It’s easy to fall into the trap of thinking the best way to make your build look good is to simply make it as big as possible, especially in 1.18’s larger worlds. In reality, while large-scale builds can be fantastic, small builds are often just as impressive – if not more so, given the difficulties of capturing detail at a small scale in Minecraft’s cubic system.
Think about what you want your build to do – is it a house? Will it be containing some kind of storage or farm? – and build it at a scale appropriate to its purpose. From there, you can simply focus on decortaing and detaling what you have to make it look good, rather than worrying about inflating its proportions to a needlessly large level just for size’s sake.